A conventional tire building apparatus (disclosed in Japanese Patent Provisional Publication No. 2-107432 or No. 107432/1990 (Japanese Patent Application No. 63-259533 or No. 259533/1988)) will be described with reference to FIG. 9. In this figure, reference numeral 1 denotes a band drum, 2 denotes a shaping drum, and 3 denotes a belt drum. The number of these drums is one each. The tire building apparatus comprises the band drum 1, the shaping drum 2, and the belt drum 3.
A housing 7 supports the shaping drum 2 and the belt drum 3. The above three drums 1, 2 and 3 are arranged on the same axis. Between the band drum 1 and the shaping drum 2, a band transfer 4 is disposed in such a manner as to reciprocate along the aforesaid axis. Between the shaping drum 2 and the belt drum 3, a belt transfer 5 is disposed in such a manner as to reciprocate along the aforesaid axis. A tread servicer 6 is disposed on the operator side (front position).
The conventional tire building apparatus shown in FIG. 9 builds ordinary tires. Since the band drum (band forming drum) 1 is dedicated to assembling an inner liner, carcass, etc., the operation time for the band drum 1, the shaping drum 2, and the belt drum 3 is distributed and uniformed, thereby the tire building time for the whole tire building apparatus being shortened. Further, since the three drums 1, 2, and 3 are arranged on the same axis and the band transfer 4 and the belt transfer 5 reciprocate between these drums 1, 2, and 3 along the aforesaid axis, the band transfer 4 and the belt transfer 5 operate efficiently.
Recently, a demand for higher speed of tire building has increased, and there arisen a need for winding a narrow member with a width of about 10 mm, usually called jointless, endless, etc., on the upper layer of the breaker in a spiral form. This significantly increases the operation time on the belt drum 3; sometimes the operation time becomes about double the conventional time. When a tire is built on the tire building apparatus shown in FIG. 9, although the tire building time for the whole tire building apparatus is shortened by distributing and uniforming the operation time for the three drums 1, 2, and 3 as described above, the operation time for the belt drum 3 is increased, so that it has a problem that the tire building time for the entire tire building apparatus is approximately doubled.
On the other hand, each process of the tire building apparatus has been automated, so that one operator handles two tire building machines. For this reason, there has arisen a need for arranging two tire building apparatuses in opposing relationship by arranging the tread servicer 6 on the side opposite to the operator (rear position).
In order to wind jointless etc., the need for distribution of increased operation time on the belt drum 3 leads to the installation of two belt drums 3.
To wind materials in a sequence of, for example, No. 1 belt, No. 2 belt, cap strip, and tread, and to repeatedly perform the removing operation at the belt transfer 5, it is necessary that two belt drums 3 can be oscillated or cyclically moved.
In this case, however, it is impossible to mount the shaping drum 2 and the belt drum 3 to the same housing 7 as with the conventional tire building apparatus shown in FIG. 9. Two belt drums must be mounted to an independent housing as shown in FIG. 10.
In FIG. 10, two belt drums 8a and 8b are mounted to a housing 10 rotatably supported by a stand 9. The housing 10 is provided with a driving unit for driving each of the belt drums 8a and 8b. The housing 10 can be oscillated 180 degrees on the stand 9.
After a belt and tread assembly completed at the E--E line position in FIG. 10(a) and FIG. 10(d) is removed, No. 1 belt is wound around the belt drum 8b by means of a No. 1 belt servicer 11, and No. 2 belt is wound around the belt drum 8b by means of a No. 2 belt servicer 12. At the same time, at the D--D line position in FIG. 10(a) and FIG. 10(c), a jointless is wound around the belt drum 8a by means of a jointless servicer 13, and a tread is wound around the belt drum 8a by means of a tread servicer 14. Then, the belt drums 8a and 8b are rotated 180 degrees, and the above operations are repeated at each position.
FIGS. 11 through 13 show examples of conventional tire building apparatuses in which one operator can handle two belt forming machines 101 by adopting the above-described constitution.
In the tire building apparatus shown in FIG. 11, a band drum 1 and a shaping drum 2 are arranged on the same axis in opposing relationship, and a band transfer 4 is arranged between them so as to be movable in the X direction. A belt forming machine 101 is arranged on the aforesaid axis on the side opposite to the shaping drum 2 with respect to the housing 15.
Therefore, the belt transfer 5 must be moved over the housing 15 in the X-Z direction or X-Y direction (refer to 5'). This makes the construction of belt transfer complex, so that its accuracy control becomes difficult. In addition, when the belt transfer moves in the Z direction, its operation speed cannot be increased, and there is the danger of falling.
In the tire building apparatus shown in FIG. 12, a band drum 1, a shaping drum 2, and a band transfer 4 are arranged in the same manner as with the tire building machine shown in FIG. 11. However, a belt forming machine 101 is arranged in parallel to the shaping drum 2 on the side opposite to the operator (rear position).
Therefore, the belt transfer 5 need not be moved in the Z direction, but must be moved in the X-Y direction (refer to 5'). This makes the construction of belt transfer complex, so that its accuracy control becomes difficult. In addition, if any trouble occurs on the belt drum, it is dangerous and difficult for the operator to obtain access to the belt forming machine 101.
In the tire building apparatus shown in FIG. 13, a band drum 1 and a belt forming machine 101 are arranged on the same axis, and a shaping drum 2 is arranged in parallel to the aforesaid axis on the side opposite to the operator (rear position).
Therefore, a band transfer 4 and a belt transfer 5 need not be moved in the Z direction, but must be moved in the X-Y direction (refer to 4' and 5'). Moreover, because the movement range of them overlaps, the band transfer 4 is moved on an X-Y table disposed on the floor and, on the other hand, the belt transfer 5 must be moved while being hung down from an X-Y table disposed on the ceiling. It has another problem that this makes the construction of belt transfer complex, so that its accuracy control becomes difficult.